In 2009 when there was talk of libertarian influence among Tea Partiers, I wrote that it wouldn't be long before conservatives, moderates and liberals started marginalizing libertarian ideas. Well, they didn't marginalize libertarian ideas, per se, becasue they never addressed the ideas. Mostly, moderates and liberals marginalized the Tea Party by framing it is as hardcore and anti-government in the vein of Timothy McVeigh, the cartoon version of rightwingers as kooks in Montana cabins with machine guns and hand grenades guarding against mind-control and black helicopters. Then they associated libertarian influence with the cartoon fanatic. I haven't seen a moderate or liberal critic of libertarianism address libertarian ideas, and I've found no evidence they've read the rich libertarian literature from Bastiat to Mises to Nock to Rothbard to Woods. Most moderate and liberal critics reveal their lack of knowledge of libertarian ideas by criticizing libertarians on positions most libertarians don't take, such as promoting no government at all, supporting Big Corporations and advocating the abolition of regulation.
The majority of libertarians I know and have read believe at least a minimal State is necessary to protect individual rights, and most libertarians support a free market which would hurt most Big Corporations by allowing free competition from small and medium size companies which would become a threat to large sluggish corporations, and most libertarians understand that in a free market the public would likely create regulation/consumer protection sources, and companies would welcome the oversight in order to instill confidence in the public regarding their products or services.
Social conservative groups have attempted to marginalize libertarians, because social conservatives believe libertarians are drug users, pornographers and profligate libertines who want no restrictions on their risque lifestyles. This was mainly how Rick Santorum criticized libertarians -- he also had obviously never read the literature. Just because a libertarian believes that if an adult wants to smoke pot, he or she should be free to make that decision, or if an adult chooses to create or look at pornography and it only involves adults who consent, then a free society should allow this, doesn't mean that the libertarian approves of either the use of pot or the creation of pornography. The libertarian believes that morality is a part of the national debate, not a subject of legislation and coercion. Keeping government out of our bedrooms and private lifestyle choices is a matter of liberty. If a religion believes that these actions are immoral, then they have the freedom to condemn the actions and attempt to influence people to stop, but they shouldn't be able to coerce adults against their free wills as long as the free adults' actions aren't violating the rights of others.
This is basic libertarian stuff, but it has been ignored in media in favor of cartoon version attacks by political forces afraid of libertarian influence. The reason there is fear of libertarian influence is not because of pot use or pornography or Big Corporations taking over or unregulated goods killing people -- no, it's because libertarians propose to limit the power of government and increase the power of ordinary people in the private sector through a free market. This terrifies statists on the Right and Left whose world views hinge on State power and legislation to enforce their world views and implement their plans for collective action.
There's a faction of conservatives, New Republicans, and a few real liberals, like Glenn Greenwald, in the public spotlight who welcome libertarian influence and maintain libertarian ideas themselves. We'll see if the libertarian influence is real or whether statists successfully marginalize libertarians. If the last defenders of liberty are snuffed out, it won't be long before Americans realize why liberty was so important in the first place.